This project will extend the longest existing study of annual performance by tropical rain forest trees (at La Selva, Costa Rica, since 1983). A globally-significant finding has been strong inter-year changes in growth of the canopy-level trees, paralleling the variation in CO2 emissions to the atmosphere from the tropics. The reduced tree growth in hotter years suggests that declining tropical rain forest productivity could be a large positive feedback to global warming. The next five years will reveal whether the forest can acclimate, slowing the current decline in growth. One new focus will be juvenile trees; large-plot data have recently suggested they are declining around the tropics. The study will also be scaled-up spatially by mapping all the very large trees over a large landscape and using high-resolution remote-sensed data to monitor their responses to climate-change, thus paving the way for such monitoring around the world tropics.
The findings of this research have large societal and policy implications. The project will continue to involve major investment in communicating the results broadly, in research talks to dozens of student groups visiting La Selva annually, at US universities and at international meetings, through interviews with the media, and in briefings to policymakers. The long-term data are freely accessible, and the principal investigators will continue to maximize the value of the study through research collaborations.
